As water resources are rapidly being polluted, significant attention is now being paid to recovery of these waters through desalination and/or purification. In particular, with the adoption of horizontal drilling and hydraulic fracturing techniques to unlock the extensive natural energy resources from shale formations, issues regarding contaminated water from shale development are coming to the fore. Increasing development of shale gas sources has brought up an environmental issue concerning proper treatment of the often highly contaminated flowback or produced water. This produced water commonly contains various suspended solids as well as relatively large amounts of salts, often 1-5 times higher than seawater. Currently available technologies for desalination and treatment of produced water (e.g., thermal evaporation and reverse osmosis) are expensive because of multiple pretreatment steps necessary to remove suspended solids such as oil and organics, significant energy requirements for desalting, and the cost of equipment. In addition to produced water from shale development, a demand for economical purification of contaminated ground water is increasing globally.
In related applications [1], we presented the concept of ICP desalination such that each concentrate and dilute stream generated between two identical Ion Exchange Membranes (IEMs) can be separately acquired. Comparatively, conventional electrodialysis (ED) utilizes both Cation Exchange Membrane (CEM) and Anion Exchange Membrane (AEM) as shown in FIG. 1. Since different ionic diffusivity causes different thicknesses of ICP (ion depletion and enrichment) zone near the membrane, desalination performance could change depending on the kinds of major ion present in the source water and the installed membrane (CEM or AEM). Based on our analysis, CEMs in NaCl (Sodium Chloride) show better salt removal and current utilization/energy efficiency than electrodialysis (ED) [2] driving us to move towards developing ICP desalination for energy-efficient technology.
With the global market for water desalination/purification showing considerable growth and comprising variously segmented target sources, significant commercial opportunities exist for cost-effective water desalination and purification processes. The operational advantages of effectively and efficiently dealing with ultra-saline water coupled with the ability to simultaneously remove suspended solids could drive ICP to emerge as the preferred technology in the shale development industry. Although Reverse Osmosis (RO) is economical and dominant in the non-thermal desalination market, it is not economically viable for treating ultra-saline water (>40,000 ppm total dissolved solids, TDS). Thus, the shale development industry typically employs energy-intensive thermal desalination. [8]
Solutions for addressing these needs call for:
                a) Adaptable technologies for desalination of waters comprising a wide range of salinities, such as brackish water, seawater and produced water.        b) Technologies and methods which permit en bloc desalination/purification of contaminated waters; i.e., technologies that demonstrate simultaneous elimination of a range of suspended solids such as red blood cells, crude oil-in-water emulsion, and salts.        c) Cost-effective multi-stage strategies which leverage and improve technologies such as Ion Concentration Polarization (ICP).        